The flammability of wood is a major challenge for the application of wood-based products, in particular for use in construction or the production of furniture. Therefore, various approaches for improving the fire retardancy of wood have been proposed so far, for instance the addition of fire-retardant substances, the chemical modification with conventional fire-retardants, the development of wood-inorganic composites or the deposition of flame retardant coatings. Fire-retardant agents can be incorporated by spraying, dipping, brushing, immersing or pressure-impregnation. Phosphorous- or nitrogen-containing compounds based on urea or melamine show flame-resistant potential and also boron-based compounds have been employed in fire-retardant systems, for instance mixtures of ZrO2-B2O3, boric acid and borax in a melamine formaldehyde resin or borates combined with a varnish coating. Halogen-compounds offer fire-retardant features through free-radical quenching and extended char formation. Wood-inorganic composites based on silica or titania can be incorporated through sol-gel reactions. Further, complexes of silic and boric acid or nano-silver have been investigated in view of fire retardancy. However, these treatments also entail drawbacks such as a reduced mechanical performance of timber products or the release of leachable or volatile, toxic compounds causing environmental hazards.
A major drawback is the precipitation of salts at the wood surface which can impede a solid wood treatment.
The objective of the present invention is to provide a novel, cost-efficient and simple industrial modification process of wood mineralization to produce mineralized wood material with improved properties, in particular an improved fire retardancy. The object of the invention is further to provide novel, mineralized wood materials with improved properties, in particular an improved fire retardancy. This objective is attained by the subject matter of the independent claims.